Common material types of carbon steel flanges

What are carbon steel flanges?

Carbon steel flanges (CS flange) are flanges or end flange connectors whose main body material is carbon steel. It usually consists of three parts: flanges, gaskets, and bolts. It is used for the connection, distribution and control of pipelines, as well as for bearing mechanical effects such as pressure, load and shear force.

Characteristics of carbon steel flanges:

1. High strength: Carbon steel has good strength and toughness, which enables carbon steel flanges to withstand greater pressure and load when connecting pipelines.
2. Low cost: Compared with pipe flange products made of other materials, carbon steel flanges have lower production costs, so they are more affordable and widely used in various fields.
3. Good sealing: Carbon steel flanges have two sealing surfaces, and the sealing surface materials widely use various plastics, which can achieve complete sealing and prevent medium leakage.

4. Convenient disassembly and maintenance: Compared with other pipe fittings, carbon steel flanges are more convenient to disassemble and repair. There is no need to disassemble the entire pipeline system, only the corresponding flanges need to be disassembled.

Common material types of carbon steel flanges:

The material of carbon steel flanges is mainly carbon steel, including low carbon steel, medium carbon steel, high carbon steel, etc. Common materials include cast carbon steel grade WCB, forging A105, or Q235B, A350, 10#, 20# steel, 16Mn, 45# steel, Q345B, etc. The following is an introduction to some materials of carbon steel pipe flanges:

1. 20# steel flange

20# steel flange is a commonly used carbon steel flange material with a steel grade of 20Mn. It has excellent weldability and processability, but low heat resistance. It is suitable for low pressure and general temperature occasions, such as connections on water, steam and other pipeline systems.

A234 WPB material implements the ASTM A234/A234M standard, which is a standard for forged carbon steel and alloy steel pipe fittings in medium and high temperature environments formulated by the American Society for Testing and Materials (ASTM). A234 WPB steel has good mechanical properties, including high yield strength and tensile strength, not less than 240MPa and 415MPa respectively. These properties make A234 WPB steel suitable for pipeline systems subject to certain pressures and temperatures.

In China, A234 WPB steel is often regarded as equivalent to certain carbon steel materials, such as 20# steel or Q235 steel. However, it should be noted that although these materials are similar in some aspects, they may differ in chemical composition, mechanical properties and specific application scenarios.

2. Q235B flange
Q235B flange is an excellent low carbon steel with good plasticity and weldability. It is a commonly used material. Its corrosion resistance and mechanical strength are weak, and it is mainly suitable for some common occasions, such as connections on pipeline systems such as tap water and natural gas.

3. A105 flange
A105 flange is a commonly used American standard carbon steel flange material, also known as ASTM A105. It has excellent weldability, plasticity and mechanical properties, and is resistant to high temperature and high pressure, and has good corrosion resistance. It is often used for connections on high-pressure and high-temperature pipeline systems in industrial fields such as petroleum, chemical, and electric power.

4. A350 flange
A350 flange is a low-temperature carbon steel flange material, also known as ASTM A350 LF2. It has good toughness, low-temperature resistance and high corrosion resistance. It is suitable for pipeline systems under low temperature conditions, such as LNG, liquefied petroleum gas, low-temperature natural gas, etc.

5. Other flange materials
In addition to the above-mentioned pipe flange materials, there are also some carbon steel flange materials suitable for special occasions, such as A694 F52, A694 F60, A694 F70, etc. These materials are usually used for connections on fluid conveying systems of special materials.

Application areas of carbon steel flanges:

Carbon steel flanges are widely used in petroleum, chemical, power station, shipbuilding, food processing and other fields. Specifically:

1. Petroleum and chemical industry
Carbon steel flanges are usually used to connect pipelines, pipeline equipment, container equipment, etc., such as heating furnaces, heat exchangers, reactors, etc.

2. Shipbuilding field
In shipbuilding, carbon steel flanges are used to connect pipelines, oil tanks, water tanks and other equipment. Since ships are in the offshore environment, carbon steel flanges need to have strong corrosion resistance and sealing performance.

3. Food processing field
Carbon steel flanges also play an important role in the connection of equipment such as food delivery pipelines, reactors and storage tanks. At this time, products that meet hygiene standards must be selected to ensure food quality.

Precautions for carbon steel flanges:

1. Choose high-quality products: When purchasing carbon steel flanges, you should choose reputable and reliable production factories and suppliers to ensure that the material, size and tolerance of the product meet the relevant standards.

2. Pay attention to the use environment: Carbon steel flanges have relatively poor corrosion resistance and are not suitable for the transportation of some corrosive media. Therefore, when choosing carbon steel flanges, you need to fully consider whether the use environment is corrosive.

3. Strengthen maintenance: Regular cleaning and maintenance of carbon steel flanges can extend their service life and maintain their good performance. At the same time, during disassembly and maintenance, it is necessary to follow relevant operating procedures to avoid damaging the sealing surface and structure of the flange.

In summary, carbon steel flanges are low-cost, high-strength, good sealing and easy to disassemble and repair connectors, which are widely used in various fields. When selecting and using them, it is necessary to pay attention to factors such as material, size, tolerance and use environment to ensure the reliability and safety of the product.

Read more: Standard sizes of pipe flanges or How to choose pipe flange material?